Valve device



March 14, 1933. T. F.-sTAcY 1,901,131

VALVE DEVIC E March 14, 1933. T FQ ST'ACY v1,901,131

VALVE DEVICE Filed May 1o, 1929. 5 sheets-sheet 2 March 14, 1933.

Mmm

T. F, sTAcY VALVE DEVICE Filed May l0, 1929 HHI 3 Sheets-Sheet 3 Patented lil/lar. 14,

THOMAS F. STAOY, OF PIQUA, OHIO, AssIGNoF. To THE FRENCH OIL MILL MACHINERY CO., OF PIQUA, OHIO VALVE DEVICE Application filed May 10, 1929. Serial No. 362,074.

This invention relates to valve devices for With the invention, but illustrating another fluid operated presses and the like, and parembodiment thereof; ticularly to the control of iiuids utilized to Fig. 6 is a sectional plan of the saine, the Operate a press, section being taken approximately along the An object of the invention is to generally line 6`6 of Fig. 5; 55

improve and simplify the construction and Fig. 7 is a transverse, sectional elevation of operation of such valve devices. the saine, with the section taken approxi- Another Object of the invention is to promately along the line 7 7 of Fig. 6; v vide an improved valve device of this type, Fig. 8'is another transverse, sectional ele- 10 with which a plurality Of Operations of the vation of the same, the section being taken 60 press may be obtained by a single controlapproximately along the line 8--8 of Fig. 6; lfng element; With which the controlling eleand ment may be easily operated into its different Fig. 9 is a sectional diagram illustrating operating positions with a minimum of efthe relation of the main valve element to its fort; with which the operating or controlling seats, which is the same in both illustrated 65 member will be held automatically in the difembodiments of the invention. ferent operating positions into which it may In the embodiment of the invention illusbe moved; and with which discharge of fluid trated in Figs. 1 to 4, and 9, the improved under pressure from the source of supply divalve device includes a casing 1 having a rectly into the exhaust connection during oplongitudinally extending chamber 2 therein 70 eration of the' valve controlling element from which is closed at its ends by removable plugs one operating position to another will be prev 3 and 4f- The Casing iS alSO provided With vented. 1 a lateral extension 5 having therein sepa- A further object 0f the invention is to prorate auxiliary Chambers 6 and 7 Which are in Vide an f'mproved valve device 0f this type communication with the chamber 2 at dif- 75 which will be relatively Simple, Compact, efferent points along the same. The extension cient, economical in'use, practical and ineX- 5 1s provided With a port 8 (Figs. 2 and 4) pensive. to which is connected a pipe 9 for supplying Various other objects and advantages Will ,a fluid Undef a Telatlvely 10W PTGSSUF@ t0k 50 be apparent from the following description the Chambe' of two embodiments of the invention, and the The @Xtenglon 5 1S also Pfollded Wlth a novel features will be particularly pointed Second and Separate Port. 10 (F1g5- 2 and 3) Out hereinafter in connection With the aptowhch is Connected l'pipe 1,1 for Supplying ended Claims. a fluid under a relatively high pressure to In the accom anvil, drawinos: the chamber 7. rlhe casing .is also provided, 85 Fig. 1 is aplongitiidinal, scectional plan mtrmidmte of lts ends" Wlth a port 13 to through a valve device constructed in acwhich 1S Connected al P1P@ 14 leadmg to the cordance with this invention; fling Opelated press iohbe Operate/da for Sup- Fig. 2 is a side elevation of the same, with p 5mg y t e press Wit an Operatmg Hmd under iessure. The Casin(y 1 is also ro- 90 @ruim parts m 5910161011 approxlmately along vided Iaidjacent one end ofbthe chambeg 2 the line 2 2 of Fig. 1; 'l

t With an exhaust port 15 to which is connected Fig. 3 is a transverse, sectional elevation RPPVOXUUGLV donfthe mm3-3 0f Fg- 15 of the latter, and the exhaust poit 15 is 95 Img. lllOlllPl tTflllSVfFl'SQ, FQCtlOllll elegu'laun'ed at the Opposite end 0f the Cham.. ration of the saine, with the section taken ber 2b approximately along the line 4 4 of Fig. l; The port 13 may be referred to as an inter- Fig. 5 is a .side elevation of another mediate port in that it opens into the chamvalve device also constructed in accordance ber 2 at a point intermediate the ends of the 100 same and between the low pressure port 8 and the exhaust port 15. The chamber 2 is provided with an annular seat 17 and through the passage or area enclosed by this seat, fluid must pass from the low pressure inlet chamber 6 to the press connection port 13.

Similarly, a valve seat 18 is arranged across the chamber 2 between the intermediate port 13 and the exhaust port 15. The seats 17 and 18, in this particular example, are annular seats facing in opposite directions away from one another.

A valve element 19 extends into the chamber 2 of the casing 1 from one end thereof, such as through one of the removable plugs 4, and is slidingly mounted forreciprocation in the plug 4 and also in a cavity or recess 20 in the opposite end plug 3. This valve element is provided with a closure section 21 adjacent its inner end which moves into and out of closing engagement with the seat 18V when the valve element is reciprocated. The valve element is also provided with a second closure section 22 which similarly is shifted into and out of closing relation to the seat 17 by reciprocation of the valve element.

The two closure sections 21 and 22 may be shoulders, flanges or enlarged sections on the valve element, and they are spaced apart along the length of the valve element a distance greater than the distance between the annular seats 17 and 18, so that when one closure section is in engagement with its related seat, the other closure section will be well away from its related closure seat. The valve element, by its reciprocation, will thus connect the press connection port 13, which is the intermediate port, alternately with the exhaust port 15 and the low pressure inlet port 8. A suitable packing gasket 23 may be provided for the valve element where it passes through the removable plug 4 to the exterior of the casing.

The area of the valve element at the section which passes through the packing gasket 23 is greater than the area enclosed by the seat 18, as shown exaggerated in the diagram of Fig. 9, and there is therefore a definite force outward ofthe valve element when the v closure section 21 is in engagement with the seat 18. This outward force or pressure will of itself hold the valve element in its end position in which the seat 18 is closed, when Ehe valve has been operated into that posiion. i If now the valve element 19 is reciprocated 1n the opposite direction to carry the section 21 away from seat 18 and carry the sect1on 22 into engagement with the seat 17. as shown 1n Fig. 1, it will be noted that the valve element willbe similarly held in its other closed position. This holding of the valve element in its other end position, as shown 1n Fig. 1, is due to the fact that the area of the valve element in the section which passes through the gasket 23 is less than the area enclosed by the seat 17, as also shown exaggerated in the diagram of Fig. 9. It will therefore be observed that the valve element will be pressure held in both of its extreme positions. y

In order that there be no direct possible communication between the opposite ends of the chamber 2' during operation of the valve element, which would cause a temporary loss of fluid under pressure from the inlet cham# ber 6 directly to the exhaust port, the valve element may also be provided with piston sections 24 and 25 which extend toward one another from the closure sections 22 and 21 respectively.

These piston sections are ofa size to pass freely into and along, but yet close the passages that are enclosed or defined by the seats 17 and 18, one piston section being in the passage defined by its related seat when the other piston section is yentirely out of the passage defined by its related seat. The lengths of these piston sections, measured in the direction of the length of the valve element, will be such that each piston section will not leave its related passage when moving in an opening direction until the other piston section has entered, or is at the entrance to, its related passage, as shown in Fig. 1. The piston sections should move lfreely alongl their related passages, and while there may be some slight leakage along the same, nevertheless they effectively prevent any material loss of fluid between the end ports 8 and 15 during movement of the valve element.

In order to assemble a valve element having the oppositely facing closure sections 21 and 22, the valve element may be made in two part-s A and B. The part A consists of one end of the element with its closure section 21 and piston section 25, and a stem portion v prevent leakage along the interior of the sleeve forming the part B. The stem portion 26 extends entirely through the sleeve of part B, and is threaded to receive an operating head 28.

The forked end of this head 28 is connected by pivot pin 29 to an operating handle or lever 30, which is also pivotally connected by pin 31 to one end of a link 32, the link being pivotally connected at its other end by a pin 33 to a lug extending from the casing 1. The head 28 when threaded along the stem 26 engages with the sleeve of the part B and forces the latter against the shoulder 27 of the stem, so as to unite the two parts A and B into a rigid structure and to close the passage through the sleeve of the part B. A gravity operated, free check valve 34 (Figs. 2 and 4) is disposed in the chamber 6 in alignment with the lowpressure inlet port S, and is mounted and guided for reciprocation in a removable plug 35. r1`he inner or lower endV of the valve 34 has radial arms or guides 36 which slidingly fit a seat ring 37, and the Valve 34, intermediate of its ends, is provided with a closure section 38 which moves into and out of engagement with the seat ring 37 when the valve 34 reciprocates endwise of itself. l 'lhe valve opens freely by any excess o pressure inthe pipe 9 over that inchamber 6, so that fluid may pass freely from the pipe 9 into the chamber 6 and thence into the chamber 2, but when pressure in the cham ber 6 exceeds the pressure in the pipe 9, the valve 34 will automatically close for a purpose which will appear shortly. To enable the valve 34 to slide freely in the plug 35,

the valve may have one or more passages 39 connecting the end received in the plug 35 with the sides of the valve element adja cent the closure section 38, but at the upper side thereof, as shown in Figs. 2 and 4.

r1`he auxiliary chamber 7 communicates with chamber 2 at a point between the two seats 17 and 18, and will always be directly in communication with the press connection port 13 as shown in Figs. 1 and 3, regardless of the4 position of the valve element 19.

A valve seat ring 40 (Figs. 2 and 3) is disposed across the chamber 7 for controlling communication with the port 10, and the cas ing 1 is provided with a removable plug 41 whiclris in alignment with the ring 40. A hollow, cup-shaped member 42 is slidingly mounted in the inner end of the plug 41, and is provided at its closed end with a tail 43 which is slidingly mounted or guided in a passage 44 of a partition across the plug 41, as shown in Fig. 3. A disk 45 is provided in the plug 41 at the opposite side of the partition and bears against the tail 43.

A heliral spring 46 is`compressed between the disk 45 and the opposite and removable end 47 of the removable plug 41. A screw 43 may be threaded through the removable end 4T of the plug 41 to engage a disk 49 which serves as an adjustable abutment for the outer end of the spring 46. By adjustment of the screw 48the extent of compression of the spring` 46 may be varied. The plug 41 may have a vent 50 in the section housing the spring.

The member 42. at its open end, mounts another valve member 51 which is adapted to reciprocate and rotate in the open end ofthe member 42. At its lower end the member 51 is provided with a closure section 52, which engages with the seat ring 40 to close comm' lication between the chamber 'Z and the high pressure inlet port 10. The member 51 may have one or more grooves 53 running lengthwise thereof, and also endwise across the inner end of the same, so that the same pressure will be exerted on all faces of the member 51 which are within the member 42. The member 42 may also be engaged by a vgasket element 54 which is secured in position against a seat by theremovable plug 41. The members 42 and 51 together form a valve member in two sections whose upward movement is yieldingly opposed by the spring 46, and the inner section or member 51 may rotate and reciprocate within the outer section or member with comparative freedom. llfith such freedom of movement for member 51, cutting of the valve seat ring 40 and of the closure section 52 during use of the valve device will be prevented. Y

When the pressure in the auxiliary chamber 'l' at the dischargeside of seat 40, which is always in communication with the press connection port 13, reaches a predetermined pressure, the members 42 and 51, whose exposed area at the lower ends is larger than the area enclosed by the seat ring 40, will be forced upwardly against the action of the spring 46, and fluid under a relatively high pressure may then pass freely from the pipe 11 through the auxiliary chamber 7 and press connection port 13 to the press to continue to build up pressure in the press.

1n relating the operation of this valve device, let it be assumedthat the valve element 19 is in the position shown in Figs. 1 and 2. At that time, the closure section 22 will shut olf from the intermediate or press connection port 13, all communication with the low pressure inlet pipe 9, that is, with the end port 8. The intermediate port 13 will thenbe in direct 'communication with the exhaust port 15 andthe pressure in the press will be only the back pressure onthe exhaust pipe 16.

The pressure in the intermediate section of the chamber 2 will be very small, and will correspond to the pressure in the exhaust pipe. Consequently, there will be no force acting to shift the high pressure change valve 42 and 51 upwardly except the pressure within the seat ring 40. rThe passage in the seat ring 4() is relatively small. and sufh upward pressure, because of the relatively small area of the passage within the ring 40, will be insufficient to overcome the downward pressure of the spring 46, with the result that the seat ring 40 will be held closed.

1f now it is desired to admit pressure 'to the press, the valve handle 30 is operated to the left (in Fig. 2) and during that movement. the closure section 22 of the valve element 19 will move to uncover the seat 17, and the closure section21 will move into closing engagement with the seat 18. During this movement. the piston section 24 associated with the closure section 22 will not leave thel passage enclosed by the seat 17 until the piston section associated with the other closure section 21 has entered the passage enclosed by the seat 18, and therefore the fluid under pressure entering from the auxiliary chamber 6 cannot pass directly to the exhaust. The fluid under pressure from pipe 9 enters freely because flow in this direction is permitted by the free check valve 34.

The press (not shown) will then operate until the resistance increases, at which time the pressurein the intermediate section of the chamber 2 increases toward approximately the pressure in the low pressure supply pipe 9. When the pressure in the intermediate section of the chamber 2, and in the auxiliary chamber 7 which always is in communication therewith, increases to a predetermined pressure, less than the pressure in pipe 9 of course, the valve members 42 and 51 will be lifted by the pressure thereon in the chamber 7, and immediately fluid under high pressure will flow from pipe 11 through chambers 7 and 2 into the press connection pipe 14 until the pressure at the press reaches that of the ingoing high pressure.

As the pressure in the chamber 2 builds up above that of the low pressure Huid supply, the free check Valve 34 will seat itself automatically, so as to prevent reverse flow into the low pressure supply pipe 9. After the desired high pressure has been maintained for the desired interval, the valve handle 30 may be operated to the right, in Fig. 2, to return the valve element to the position shown in Figs. 1 and 2, whereupon the pressure in the press pipe 14 will be released, owing to its connection to the exhaust port 15, and original conditions will be reestablished.

Considering now the embodiment of the invention illustrated in Figs. 5 to 8, and 9, the construction is similar to that described in connection with Figs. 1 to 4, except for delails which will now be explained. Parts in Figs. 5 to 8 which correspond to those found in Figs. 1 to 4 will be given the same reference characters. The valve element 19, (Figs. 5 to 8) at its outer end is' pivotally connected by a pivot pin to links 56, which in turn are pivotally connected by a pin 57 to the operating lever 30.

The lever 30 is also connected by a pivot I pin 58 to a bracket 59 secured to one end of the casing 1a which is generally similar to the casing 1 of Figs. 1 to 4. The valve element 19 is the same as explained for Figs. 1 to 4. The low pressure check valve element 34a is similar to the valve 34, except that the guide arms 36 are omitted. The automatic change valve for controlling the admission of a fluid under high pressure is somewhat different than that explained for Figs. 1 to 4, in that the high pressure itself tends to hold its own controlling valve closed.

Referring particularly to Fig. 7, the two section valve member formed of members 42 and 51 of Figs. 1 to 4 is replaced by a valve stem or member 60 which extends loosely through the passage of the ring 40 and slidingly through the walls 61 and 62 defining part of the chamber 7. The lower end 63 of the stem 60 reciprocates in a removable plug 64 which compresses suitable packing 65 between it and the removable end wall 62.

The valve stem-60 has a closure section 66 which engages with the seat ring 40 at the high pressure supply end of the ring, so that the pressure at the upper end of the chamber 7 will normally hold the 'valve stem 60 in closed position. The upwardly projecting end of the valve member 60 passes through suitable packing 67 and a plug 68 which is disposed in or threaded into a recess in the upper side of the casing. A plug 69 is removably secured in the open end of this cavity in the upper face of the casing 1a, and this plug 69 has a piston chamber 70 at its open lower end, in which reciprocates a piston 7l mounted on the projecting end of the valve member 60. A spring 46 is compressed between a washer 7 2 fitted over the upwardly projecting end of the stem or valve member 60, and the closed end of the plug 69. The plug 69 may have suitable vents 73 and 74 which permit free movement of the piston in the chamber 70. l

A small conduit or channel Connects the lower end of the cavity into which the plug 69 is threaded with the intermediate section of the chamber 2, so that the pressure on the under face of the piston 71 at all times corresponds to the pressure in the chamber 7 at the discharge side of seat 40 and in the pipe 14 which leads to the press. When the pressure in the intermediate section of the chamber 2 increases by the inflow of fluid under low pressure, as explained in connection with Figs. 1 to 4, the upward force acting on the piston 71 of the valve member 60 will increase.

`When the force acting on the piston 71 in aV direction to lift the valve member 60 reaches a predetermined pressure, it will overcom-e the spring 46 and the downward pressure on the portion of the stem or valve 60 which is the chamber 7 above the seat ring 40, and thereupon the valve member 60 will be operated upwardly into open position. The fluid under high pressure will then flow through the auxiliary chamber 7 into the chamber 2, and thence to the press to cause an operation thereof as explained for Figs. l to 4.

When the valve handle 30 is operated to shut ofi' the supply of low pressure fluid, as when it is in the position shown in F 1g. 1

which is the opposite position from thatshown in Fig. 6, the pressure in the intermediate section of the chamber 2 will fall by teorici reason of its connection to the exhaust, and thereupon the spring 46 will force the valve member G0 downwardly into closed position. While the valve member 60 is in closed position, the pressure in the upper part ot the chamber 7 will assist spring 46 in securely holding member 60 in closed position on its seat ring. The operation of the embodiment of the invention illustrated in Figs. 5 to 8, and 9, is otherwise the same as explained for Figs. l to @and 9.

lt will be obvious that various changes in the details, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

ll claim 1. A valve device for fluid operated presses and the like, comprising a casing having a closed chamber with ports for three pipe connections spaced apart along the same and two annular seats controlling communication between the intermediate port and the other ports, a valve element extending into said chamber from outside and at" its inner end movable back and forth within the chamber to position spaced sections thereof alternately in closing positions across said seats, one of said annular seats bein-g smaller than the other and the section of the valve element in the chamber at the point where it passes out .of said chamber having a cross sectional area ot a size between the areas'enclosed by the said seats.

2. A valve device for Huid operated presses and the like, comprising a casing having a closed chamber with ports tor three pipe connections spaced apart along the same and two annular oppositely -facing valve seats controlling communication between the intermediate port and the other ports, a valve element extending into said chamber from the exterior of the casing and having spaced closure sections, said element being mounted for reciprocation to carry said closure sections alternately into and out of engagement with their seats and thus connect the intermediate port alternately with the two end ports, the section of the valve element which passes through the casing having less cross sectional area than the area enclosed by the adj acentI seat, and both of such areas being greater than the area enclosed by the other seat, whereby when a. source of pressure is connected to the port at the end of the casing where the valve element enters the casing, the intermediate port is connected to a press, and the opposite end port is connected to an exhaust connection, the valve element will be locked by pressure in both positions.

3. A valve device for Huid operated presses and the like, comprising a casing having a closed chamber with ports for three pipe connections spaced apart along the same, a source of low pressure fluid connected to one end pipe connection, a source of high pressure iuid and a press connection connected to the middle port, an exhaust connection to the other end port said chamber having two annular valve seats in said chamber controlling communication between the intermediate port and the other ports and facing the adjacent ends of said chamber, and a unitary valve element slidingly mounted solely tor reciprocation in said chamber and having spaced closure sections rigidly connected to one another in the ends ot said chamber and which alternately engage said seats during reciprocation of' the valve element, said valve element having an operating section extending out of said chamber at the end connected to said low pressure said element also having a piston portion adjacent each closure section which enters and passes through the adjacent valve seat during movement of said element in a direction to carry the adjacent closure section into closed relation on its related seat, said piston sections having diameters filling the passages in related seats and lengths such that the passage through each seat will be closed while the passage through the other seat is open, whereby direct communication between the end ports will be avoided in all reciprocating movements of said valve element.

et. A valve device for fluid operated presses and the like, comprising a casing having a closed chamber with ports for three pipe connections spaced apart along the same, a source ot low pressure fluid connected to one end pipe connection, a source ot high pressure Huid and a press connection connected to the middle port, an exhaust connection tov the other end port said chamber having two annular valve seats -in said chamber controlling communication between the intermediate port and the other ports and facing the adjacent ends of said chamber, a valve stem extending through said casing into said chamber through the end connected to said source of low pressure and mounted :tor endwise sliding reciprocation, only said stein having flanged sections fixed thereon and engageable alternately with their adjacent seats during reciprocation of said stem, whereby communication between the intermediate port and the other ports will be alternately established by reciprocation of said stem, said stein having piston sections immediately adjoining the flanged sections and extending toward one another and slidable through the seats which the vitlanged sections close, each piston section having a diameter filling the passage in its related seat and a length such that during opening of the passage through the valve seat in which it is moving, that piston section will prevent communication through that passage until the lll@ piston section associated with the other seat has entered the passage through that other seat, and will then move out of its seat to open the passage, whereby direct communication between said end ports will be prevented.

5. A valve device for fluid operated presses and the like, comprising a casing having a closed chamber with a plurality of ports for pipe connections spaced apart along the same, and two annular oppositely facing valve seats controlling communication between the end ports and an intermediate port, a. valve element extending into said chamber from the outside and reciprocating in said casing and having closure sections spaced apart along its length a distance greater than the distance between said seats, whereby when said valve element is reciprocated, said closure sections will engage alternately with said seats, the end portion of said valve element having one closure section being detachably and rigidly connected to the portion having the other section, and said closure sections and the section passing out of said chamber all being of different sizes with the closure sections the largest and smallest, whereby the valve element will be pressure held at each limit of its reciprocation.

6. A valve device for fluid operated presses and the like, comprising a casing having a closed chamber with a plurality of ports for pipe connections spaced apart along the same, and two annular opposite facing valve seats controlling communication between the end ports and an intermediate port, a valve element reciprocating in said casing and having closure sections spaced apart along its length a distance greater than the distance between said seats, whereby when said valve element is reciprocated, said closure sections will engage alternately with said seats, one end'portion of the valve element with its closure section having a threaded stem which passes through an endwise passage in the other portion havingthe other cl-osure section, said valye element extending exteiorly of the casing, and operating means detachably connected to the outer end of the valve element.

7. A valve device for valve operated presses and the like, comprising a casing having a closed chamber with a plurality of ports, for a plurality of pipe connections, spaced apart along the same and also aligned, annular, oppositely facing valve seats controlling communication between the intermediate port and the end ports, said casing having passage therethrough into said chamber in alignment with said seats, a member having a closure section engageable with one of said seats and having a stem passing through both seats and exteriorly of the casing through said passage, said stem having a shoulder thereon, a sleeve confined on said stem against said shoulder and having a section engageable with the other valve seat to'- ing a reciprocating valve element which carries said closure sections alternately into engagement with their related seats, and means connected to the outer end of said Valve element for reciprocating the same.

8. In a valve device for fluid operated presses and the like, an automatic high pressure change valve comprising a casing having a passage therethrough, a valve seat in said passage, a valve member in said casing movable into and out of engagement with said scat to close or open said passage, resilient mechanical means for urging said valve member against the direction of fluid flow in said passage into closed position, the portion of said'valve member in said passage at the discharge side of said seat having an area greater than the area engageable with said seat, whereby when the back pressure in said passage at the discharge side of said seat reaches a predetermined value, it will force said valve into open position and permit fluid flow through' said seat and said passage, said valve member including a cup-shaped section with its open end facing said valve seat, slidable toward and from said seat, and engaged and operated by said resilient means towards its seat, and an inner section freely slidable and rotatable in the cavity of said cup and having a reduced portion directly engageable with said seat to close the same when both of said sections are forced toward the seat, whereby cutting between the valve seat and valve member will be avoided, one of the sections of the valve member having a passage leading to the inner end of the inner section, whereby the pressure on the inner section will be equalized, and the inner section will be free to rotate and slide in the outer section.

9. In a valve device for fluid operated presses and the like, a casing having a chamber with ports spaced apart endwise thereof, a valve element shiftable in said chamber and controlling communication between the end ports and the ported section of the chamber between the end ports, a source of Huid under a relatively low pressure connected solely to one end port, a source of Huid under a relatively high pressure connected solely to an intermediate port, an exhaust pipe connected to the other end port, a press connection to said ported chamber section, so as to be in direct communication with said source of high pressure fluid, a check valve in the' passage for low pressure fluid to said chamber and preventing fluid flow from said chamber into said passage, a physically separate check valve in the passage through which fluid from said high pressure source enters said chamber and urged into open position` by the pressure upon a part only of the area of one end thereof by Huid from said source of high pressure which is trying to enter said chamber, a yielding mechanical device forcing said separate check valve into closed position and against said pressure on said partial end area, the balance of said end area being always directly exposed t0 the pressure in said chamber section, whereby when the back pressure in said chamber section, caused by resistance oered by the press, upon said balance of end area, and the pressure on the partial end area by the shut 0E highpressure fluid, are su'Hicient to overcome the closing pressure of said mechanical means on that separate valve, that valve will open automatically and admit high pressure fluid directly to said chamber section and thence to said press connection.

THOMAS F. STACY. 

